The overall objective of the trial is to examine the relative value of surgical versus medical treatment of ISCHEMIC NEPHROPATHY ISCHEMIC NEPHROPATHY is defined as renal insufficiency associated with severe extraparenchymal occlusive disease of the renal artery. In turn, renal insufficiency is defined as a glomerular filtration rate (GFR) less than 60 ml/min. Since the goals of management in severely azotemic patients are to minimize the frequency of major related morbid events and prolong dialysis- free survival, clarification of the impact of correction of severe renovascular occlusive disease on these goals has major significance for both the quality of survival for such patients and the health care costs associated with their management in the nation as a whole. Specifically, the objective is to allocate randomly a group of recruited patients with ISCHEMIC NEPHROPATHY to either standard medical treatment alone or surgical management (renal revascularization) combined with medical management in order to identify the impact of surgical correction of such disease on the rate of deterioration in GFR and on quality of life indicators. This trial tests the hypothesis that surgical correction of the renal artery occlusive disease will have a salutary effect on renal function status, its rate of deterioration, and, thereby, the quality of life in these patients. The primary renal function outcome of interest is the comparative effect of renal revascularization on sequential changes in GFR over a one year period of observation. Survival, dialysis-free survival, cost and utilization of health care resources, and measures of quality of life will be comparatively assessed for the duration of the study (one to five years). To perform this study, a group of 135 patients (age 18-75 years) with GFR <60 ml/min but >15 ml/min who satisfy inclusion/exclusion criteria will be randomized to either surgical plus medical treatment or medical management alone over a four-year period (34 patients each year). Following randomization and surgery (in one-half of the group), patients will be followed with serial measurements of GFR, quality of life indicators, and measures of cost and utilization of health care resources.